This application is a request for continued support of the University of Pennsylvania Smell and Taste Research Center, the first Clinical Research Center in the United State devoted solely to the study of the chemical senses. This Center provides the resources and scientific focus for interdisciplinary clinical and fundamental research related to the understanding, diagnosis, treatment, and management of patients with olfactory and gustatory disorders. Data from the National Ambulatory Medical Care Survey suggest that, for 1975 and 1976 combined, 435,000 visits to physicians'offices occurred in which a major presenting compliant was chemosensory in nature, and this Center is one of the few national institutions devoted to understanding and treating patients with these problems. The primary administrative offices and diagnostic facilities of the Center are located within the Hospital of the University of Pennsylvania. Center laboratories are located within the Schools of Medicine, Dental Medicine, and Veterinary Medicine, as well as in the Veterans Administration Medical Center of Philadelphia. The new Core Facility of the Center, in which the Center's controlled environment room and human air-dilution olfactometer are located, serves as the primary location for the Center's human studies, and is positioned adjacent to the clinical facilities of the Department of Otorhinolaryngology and Human Communication, the Department of Neurosurgery, the Department of Dental Medicine, and the Speech and Hearing Center. This prime location fosters direct interactions between our Center and these and other departments within the Hospital. The Center has now established a computer-based registry of patients studied in our facility (based upon clinical records, standardized intake interviews, and medical and sensory evaluations), providing a rich data base for the study of the etiology of chemosensory disorders, their natural history, clinical manifestations, and response to therapy. During the next five years we will further expand and analyze our core patient data base and continue our research programs on the development of olfactory diagnostic tests and the influences of neuroendocrine factors on olfactory function. In addition, we will initiate new programs on (a) low intensity laser biostimulation of neural tissue, including olfactory neuroepithelial explants, (b) neuroanatomical substrates of conditioned chemosensory aversions, (c) the relation between depressive illness and taste dysfunction, and (d) brainstem mechanisms of gustatory processing.